There will be two parts in this post :

  1. How to build run your first hadoop application in local with IntellijIDEA
  2. How to use Hadoop to explore user relationship inside GB/TB data

Part 1

You need to create a Java program with Maven as the dependency management tool.

The result will be in part-r--0000 file :

count	1
word	2

Part 2

You can find the original novel in finding-friends-with-mapreduce.